The invention relates to an inductively coupler activated completion system.
After a well has been drilled and a casing has been cemented in the well, the well is completed by lowering production tubing into the wellbore and perforating one or more portions of the casing adjacent pay zones to allow fluid from the surrounding formation to flow into the well for production to the surface. In addition, packers are set to isolate the perforated region and production valves are used to control the flow of production fluid. The packers and production valves can be electrically activated.
To perforate, perforating guns are lowered on a tool string into the well and the guns are fired to create openings in the casing and to extend perforations into the surrounding formation. In an electrically-actuated perforating system, an actuating electric current is transmitted down an electric conductor (extending through a wireline or coiled tubing) to a firing head connected to fire a perforating gun string. In a conventional electrically-actuated firing system, a continuously contacting electrical connection (in the form of electrical wires and connectors) extends from the well surface to an electric detonator in the firing head. An electric current is then transmitted through the electrical wires and connectors to activate the electric detonator and fire the perforating gun.
In other electrically-actuated firing systems, such as that disclosed in U.S. Pat. No. 4,544,035, entitled "Apparatus and Method for Use in Detonating a Pipe-Conveyed Perforating Gun," inductive coupling has been used to activate and fire a perforating gun. In the system disclosed in the '035 patent, a male conductor wire and a female conductor wire are used, in which the male and female conductor wires are separately lowered downhole. After the female coupling member is in the desired position, the male coupling member is lowered into and received by the female coupling member. An electrical alternating or pulsating current is then generated in the conductor wire of the male coupling member, and the current is inductively coupled to the conductor wire of the female coupling member. The current is used to fire the perforating gun.